Provided is a touch detection device, touch detection method, and touch screen panel, which detects a touch signal by detecting a driving back phenomenon occurring in a touch pad by a driving voltage applied to a driving capacitor, and a display device with a built-in touch screen panel. The touch detection device that is added on top of a display device and detects occurrence of a touch capacitance (Ct) by an approach of a bodily finger (25) or a touch input instrument such as a conductor similar to the bodily finger, the touch detection device comprising: a touch pad (10) that forms the touch capacitance (Ct) between the touch input instrument and the touch pad; a driving capacitor (Cdrv) whose one side is connected to the touch pad (10) and to the other side of which a driving voltage for detection of a touch input is applied; a common voltage detector that detects a common voltage generated from the display device; a driving voltage generator that generates the driving voltage in synchronization with the common voltage; and a touch detector that is connected to the touch pad (10), and that detects a touch signal by using a driving back phenomenon when the touch capacitance (Ct) is added to the driving capacitor (Cdrv) according to occurrence or non-occurrence of a touch in the touch input instrument. A touch signal is detected while avoiding a point in time of a change of a common voltage state, and a driving voltage is applied through a driving capacitor connected to a touch detector, to thus detect whether or not a driving back phenomenon occurs in the touch detector and to thereby acquire a touch signal. Accordingly, an influence due to parasitic capacitance generated by noise, coupling phenomenon or other factors is minimized, to thus acquire a touch signal stably.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A touch detection apparatus installed in a display device to sense a generation of touch capacitance Ct by approaching a touch input device of a finger of a human body or a conductor similar to the finger to the display device, the touch detection apparatus comprising: a touch pad configured to form the touch capacitance Ct between the touch pad and the touch input device; a driving capacitor Cdrv, wherein one portion of the driving capacitor Cdrv is connected to the touch pad and the other portion of the driving capacitor Cdrv is applied with a driving voltage for touch detection; a touch detector configured to be connected to the touch pad and detect a touch signal using a driving back phenomenon when the touch capacitance Ct is added to the driving capacitor Cdrv depending on whether the touch input device is touched; and a common voltage detector configured to detect a common voltage generated from the display device, wherein when the common voltage is not detected by the common voltage detector or a value detected by the common voltage detector has an error, common voltage synchronization is performed using common voltage information which is pre-stored during a factory calibration process, the common voltage information comprising the duration of a high section of the common voltage, the duration of a low section of the common voltage or a rising edge of the common voltage, the common voltage synchronization comprising adjusting the duration of the high section of the common voltage, adjusting the duration of the low section of the common voltage, or adjusting the rising edge of the common voltage.
2. The touch detection apparatus of claim 1 , further comprising: a memory unit configured to store the touch signal detected by the touch detector; and a driving voltage generator configured to generate the driving voltage in synchronization with the common voltage.
3. The touch detection apparatus of claim 2 , wherein the driving voltage is applied to one portion of the driving capacitor Cdrv in synchronization with any one of the common voltage or the charging period of the charging device.
4. The touch detection apparatus of claim 1 , wherein when the common voltage is not detected, a CPU or a signal processor of a touch drive IC extracts a duration of a non-detected common voltage among common voltage elements stored in a memory and detects the touch signal in synchronization with the extracted duration.
5. The touch detection apparatus of claim 4 , wherein the common voltage element is at least any one of a duration of a HIGH period or a duration of a LOW period of the common voltage or each duration of the HIGH and LOW periods of the common voltage in a back porch and a front porch of an image frame.
6. The touch detection apparatus of claim 1 , wherein when the detected common voltage has an error, a predetermined window is set based on a duration value of the common voltage stored in a memory and when the common voltage is not detected for a time to which the window is added in the duration which is a reference, a CPU generates a virtual common voltage as a signal required for synchronization.
7. The touch detection apparatus of claim 1 , wherein an oscillator is used to generate the common voltage and when a period of the oscillator is changed depending on a change in temperature, a common voltage elements having the changed period detected in real time are stored in a memory and are used for detecting an error.
8. The touch detection apparatus of claim 7 , further comprising: a determination device configured to select any one of the elements detected in the factory calibration and the elements detected in the real time calibration and use the selected element for the common voltage synchronization.
9. The touch detection apparatus of claim 1 , further comprising a common electrode capacitance Cvcom, wherein the common electrode capacitance Cvcom is formed between the touch pad and a common electrode of the display device.
10. The touch detection apparatus of claim 1 , wherein the driving capacitor Cdrv is not connected to the common voltage detector.
11. The touch detection apparatus of claim 1 , wherein the touch pad is connected to the touch detector or the common voltage detector.
12. The touch detection apparatus of claim 1 , further comprising a charging device for applying a precharge voltage, wherein the charging device is connected to the touch pad which is connected to the common voltage detector.
13. The touch detection apparatus of claim 12 , wherein the charging device is a switching device and an output unit of the switching device which is connected to the touch pad connected to the common voltage detector is in a high impedance state at the time of detecting the common voltage.
14. The touch detection apparatus of claim 12 , wherein the charging device maintains an off state for a predetermined period and the common voltage detector detects the common voltage in the state in which the charging device is in the off state.
15. The touch detection apparatus of claim 12 , wherein the charging device is turned on/off in synchronization with the common voltage.
16. The touch detection apparatus of claim 12 , further comprising: a device configured to set a charging period of the charging device.
17. The touch detection apparatus of claim 1 , wherein the touch detector detects the touch signal when a predetermined period lapses after the driving voltage is applied.
18. The touch detection apparatus of claim 1 , wherein an input unit of the common voltage detector is in a high impedance state.
19. The touch detection apparatus of claim 1 , wherein a signal output from the common voltage detector is input to a comparator to detect whether the common voltage is in a HIGH state or a LOW state.
20. The touch detection apparatus of claim 19 , wherein at least one of an upper reference voltage for detecting the HIGH state of the common voltage and a lower reference voltage for detecting the LOW state of the common voltage is input to the comparator.
21. The touch detection apparatus of claim 1 , wherein at least one of touch pads is sequentially connected to the common voltage detector.
22. The touch detection apparatus of claim 1 , wherein when the touch pad connected to the common voltage detector is connected to the touch detector, other touch pads which are not connected to the touch detector are connected to the common voltage detector to detect the common voltage.
23. The touch detection apparatus of claim 1 , further comprising: a device configured to output a signal of the common voltage detector to an external component separated from the touch drive IC (TDI).
24. The touch detection apparatus of claim 23 , further comprising: a device configured to determine whether to output the signal of the common voltage detector to the external component.
25. The touch detection apparatus of claim 1 , wherein a voltage detected by the touch detector at the non-touch time is determined by the following <Equation 1>, when the touch capacitance Ct is added, the voltage detected by the touch detector is determined by the following <Equation 2>, and the driving back is generated by a difference between the <Equation 1> and the <Equation 2>, Δ Vsensor = Vpre ± ( Vh - Vl ) Cdrv Cdrv + Cvcom + Cp 〈 Equation 1 〉 Δ Vsensor = Vpre ± ( Vh - Vl ) Cdrv Cdrv + Cvcom + Cp + Ct , 〈 Equation 2 〉 wherein, in the Equation 1 and Equation 2, ΔVsensor represents the voltage detected by the touch detector, Vh represents a HIGH level voltage applied to the driving capacitor, Vl represents a LOW level voltage applied to the driving capacitor, Cdrv represents a driving capacitance of the display device, Cvcom represents a common electrode capacitance of the display device, Cp represents a parasitic capacitance of the display device, and Ct represents the touch capacitance.
26. The touch detection apparatus of claim 25 , wherein the touch detector detects a touch area of the touch input device for the touch pad in response to a size of the driving back.
27. The touch detection apparatus of claim 1 , wherein a sensor signal line is positioned at left and right sides of the touch pad.
28. The touch detection apparatus of claim 1 , wherein the rest touch pads which do not perform touch detection are in a floating state.
29. The touch detection apparatus of claim 28 , wherein the touch pads which do not perform the touch detection are entered into the floating state before a charging device of the touch detector is turned on.
30. The touch detection apparatus of claim 1 , wherein after the driving voltage is applied to the driving capacitor Cdrv connected to the touch detector, the touch pad connected to the touch detector is separated from the touch detector.
31. The touch detection apparatus of claim 30 , wherein the time when the touch pad connected to the touch detector is separated from the touch detector is in 1 ns to 100 μs after the driving voltage is applied to the driving capacitor connected to the touch detector.
32. The touch detection apparatus of claim 30 , wherein the touch pad separated from the touch detector is re-connected to the touch detector or applied with a predetermined voltage after the touch detection of the touch detector is completed.
33. The touch detection apparatus of claim 32 , wherein the predetermined voltage is a ground (GND) voltage or a DC voltage having a predetermined size.
34. The touch detection apparatus of claim 1 , wherein after a touch detection operation of the touch detector is completed, a non-detection touch pad which does not perform touch detection in a floating state is applied with a ground voltage or a DC voltage having a predetermined size.
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July 16, 2015
September 20, 2016
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